/Engine/Plugins/Online/OnlineSubsystem/Source/Public/Interfaces/OnlineGroupsInterface.h
Create a new group using the specified GroupInfo. FGroupsResult::GroupId can be used to identify the newly created group once the callback executes (FGroupsResultbeing a param to the callback).
void CreateGroup ( const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) & ContextUserId, const [FGroupDisplayInfo](API\Plugins\OnlineSubsystem\Interfaces\FGroupDisplayInfo) & GroupInfo, const [FOnGroupsRequestCompleted](API\Plugins\OnlineSubsystem\Interfaces\FOnGroupsRequestCompleted) & OnCompleted )